Various printing methods are used in printing machines. Non-impact printing (NIP) methods are understood as printing methods that do not require a fixed, that is, a physically unchanging printing forme. Such printing methods can produce different printed images in each printing process. Examples of non-impact printing methods include ionographic methods, magnetographic methods, thermographic methods, electrophotography, laser printing, and in particular inkjet printing methods. Such printing methods typically have at least at least one image producing device, for example at least one print head. In the case of the inkjet printing method, such a print head is configured, for example, as an inkjet print head and has at least one and preferably a plurality of nozzles, by means of which at least one printing fluid, for example in the form of ink droplets, can be transferred selectively to a printing substrate. In this process, it is important for the distance between the printing substrate and the image producing device to be kept as constant as possible, to allow image production to be synchronized over time, while at the same time avoiding damage to the image producing device.
In the inkjet printing method, for example, particularly when water-based inks are used, the printing substrate can become deformed, for example, forming ripples. Such ripples can entail the risk of damage both to print heads and to the printing substrate, and can also lead to low print quality, for example due to the different flight time lengths for droplets of printing fluid.
US 2012/0162299 A1 discloses a printing assembly that has a plurality of print heads and stationary guide elements in the region of the print heads.
WO 03/03705 A1 discloses a printing assembly that has a row of print heads and web guiding rollers opposite said print heads, said web guiding rollers being arranged such that they can be thrown off of the print heads together in a linear manner.
US 2011/0043554 A1 discloses a printing assembly which has printing units arranged one above the other, for printing respectively different sides of a web of printing substrate. As guide elements, rollers are arranged in a common frame.
EP 0771652 A1 discloses a printing assembly that has a vertical transport path for a printing substrate web in a printing section.
JP 2005-246617 A discloses a printing assembly that has a pivotable guide element.
US 2010/0245418 A1 discloses a printing assembly with guide elements that are movable in a transverse direction.
U.S. Pat. No. 4,334,946 A discloses a printing assembly in which two web fixing devices are arranged together on a movable support body.
Known from JP 2007-147817 A is a printing assembly in which web-type printing substrate is separated into sections, which are then further processed individually.
US 2014/0176639 A1 discloses a printing assembly that has fixed guide elements, against which a printing substrate is partially suctioned by means of a vacuum.
US 2011/0150552 A1 discloses a printing assembly that has a series of guide elements.